[crazy voyager]

If a coach is DQ'ed the assistant takes over.
If there is no assistant then the captain takes over. If the captain then gets ejected the vice captain takes over and so on.
A person not in the scoresheet (like a parent) may NOT take over the job. They are not allowed in the beanch area and may not coach the team.
This is one of the reasons why every name should be in the scoresheet before the game and also why you should always make sure the captain is marked.